Sugar may make you "stupid," rat study suggests

(CBS News) A sugar-laden diet could make you dumber, according to the authors of a new study. But, don't fret: Omega-3 fatty acids may be able to mitigate the effects.

A UCLA study showed that when a fructose solution was given to rats, they had a harder time figuring out a complicated maze. However, when rats were given both the sugary substance and a supplement high in omega-3 fatty acids, they were able to get through the maze much faster than rats that didn't receive omega-3's.

"Our findings illustrate that what you eat affects how you think," said Fernando Gomez-Pinilla, a professor of neurosurgery at the David Geffen School of Medicine at UCLA and a professor of integrative biology and physiology in the UCLA College of Letters and Science, said in a written statement. "Eating a high-fructose diet over the long term alters your brain's ability to learn and remember information. But adding omega-3 fatty acids to your meals can help minimize the damage."

The findings were published on May 15 in The Journal of Physiology.

U.S. Department of Agriculture estimates show the average American consumes more than 47 pounds of cane sugar and 35 pounds of high-fructose corn syrup each year, according to the statement.

For the study, two groups of rats were fed standard rat chow and trained on a maze twice a day for five days. Landmarks were placed to help the animals navigate the challenge. Then, the sugary diet was started: One group was given a fructose solution instead of drinking water for six weeks. The other group received the fructose solution as well as flaxseed oil and docosahexaenoic acid (DHA), both of which are known sources of omega-3 fatty acids. DHA is known to protect against damage between the chemical connections between brain cells, known as synapses, which are essential for memory and learning.

The rats were then put in the same maze and were timed by researchers. Rats on the fructose-only regimen were slower and showed less synapse activity. When their brains were examined, it showed that insulin - a hormone that controls blood sugar and regulates synapse function in the brain - was less effective. Gomez-Pinilla believed that the sugar had blocked the insulin's ability to regulate how cells used and stored sugar for energy.

Researchers pointed out that the study results did not refer to consuming naturally occurring fructose in fruits, which have important anti-oxidants, but fructose used in sweeteners such as high-fructose corn syrup.

Gomez-Pinilla advises people to eat fresh berries and Greek yogurt instead of sweet deserts. He added that unprocessed dark chocolate without lots of extra sweetener was fine too. And, if you have to absolutely have that piece of chocolate cake, Gomez-Pinilla said you might want to couple that with some walnuts, flaxseeds or a daily DHA capsule,

"Our findings suggest that consuming DHA regularly protects the brain against fructose's harmful effects," said Gomez-Pinilla. "It's like saving money in the bank. You want to build a reserve for your brain to tap when it requires extra fuel to fight off future diseases."

The Corn Refiners Association responded to the study in a statement, saying, "Fructose is a common sweetener found in nature and present in fruits, vegetables, fruit juices, and many caloric sweeteners. Humans normally consume fructose in combination with glucose in all these foods and beverages. There is abundant scientific evidence demonstrating that consuming fructose and glucose together is entirely safe due to the way the body metabolizes these simple sugars in combination. As many dietitians agree, all sugars should be consumed in moderation as part of a balanced lifestyle."

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